﻿using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.ComponentModel;

namespace MyPhotoIndex.Controls
{
    public class NativeScrollBar : NativeWindow
    {
        public NativeScrollBar(Control parent)
        {
            CreateParams cp = new CreateParams();

            // Fill in the CreateParams details.
            cp.Caption = String.Empty;
            cp.ClassName = "SCROLLBAR";

            // Set the position of the scrollbar so that it is offscreen
            cp.X = -1000;
            cp.Y = -1000;
            cp.Height = 100;
            cp.Width = 100;

            // Create as a child of the specified parent
            cp.Parent = parent.Handle;
            cp.Style = WS_VISIBLE | SBS_VERT | WS_CHILD;

            IntPtr modHandle = NativeScrollBar.GetModuleHandle(null);

            IntPtr handleCreated = IntPtr.Zero;
            int lastWin32Error = 0;
            try
            {
                // Create the actual scrollbar window
                handleCreated = NativeScrollBar.CreateWindowEx(cp.ExStyle, cp.ClassName,
                                                                  cp.Caption, cp.Style, cp.X, cp.Y, cp.Width, cp.Height, new HandleRef(cp, cp.Parent), new HandleRef(null, IntPtr.Zero),
                                                                  new HandleRef(null, modHandle), cp.Param);
                lastWin32Error = Marshal.GetLastWin32Error();
            }
            catch (NullReferenceException e)
            {
                throw new OutOfMemoryException("Could not create Native Window");
            }
            if (handleCreated == IntPtr.Zero)
            {
                throw new Win32Exception(lastWin32Error, "System error creating Native Window");
            }

            // Now assign the NativeWindow handle to the native scroll bar
            this.AssignHandle(handleCreated);
        }

        // Constant values were found in the "windows.h" header file.
        private const int WS_CHILD = 0x40000000,
                          WS_VISIBLE = 0x10000000,
                          SBS_HORZ = 0x0000,
                          SBS_VERT = 0x0001;
        [DllImport("USER32.DLL", EntryPoint = "CreateWindowEx", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr CreateWindowEx(int dwExStyle, string lpszClassName,
                                                   string lpszWindowName, int style, int x, int y, int width, int height,
                                                   HandleRef hWndParent, HandleRef hMenu, HandleRef hInst, [MarshalAs(UnmanagedType.AsAny)] object pvParam);
        [DllImport("KERNEL32.DLL", CharSet = CharSet.Auto)]
        private static extern IntPtr GetModuleHandle(string modName);

    }

}
